Vehicle operation mode systems and methods

ABSTRACT

A system for controlling a mode of operation of a vehicle having a rechargeable energy storage system (RESS), an engine, and a drive motor coupled to the RESS and the engine, the drive motor selectively powered by at least one of the RESS and the engine includes a controller operable to adjust the vehicle to operate in a plurality of operating modes including a first mode in which the drive motor is powered by the RESS, a second mode in which the drive motor is powered more by the engine than the RESS. When the second mode of operation is selected, controller is configured to operate the engine as necessary to maintain the RESS at or above a predetermined state of charge.

CROSS-REFERENCE TO RELATED PATENT APPLICATIONS

This application is a continuation of U.S. patent application Ser. No.13/847,705 filed on Mar. 20, 2013, which is a continuation of U.S.patent application Ser. No. 13/569,886 filed on Aug. 8, 2012, whichclaims priority to U.S. Provisional Patent Application No. 61/550,015filed on Oct. 21, 2011 and is a continuation-in-part of U.S. patentapplication Ser. No. 13/197,608 filed on Aug. 3, 2011, which claimspriority to U.S. Provisional Patent Application 61/370,561, filed onAug. 4, 2010. Each of the foregoing applications are incorporated hereinby reference as if set forth in their entireties.

BACKGROUND

The present disclosure relates generally to hybrid or electric vehicles,and particularly to a plurality of operating modes associated withhybrid or electric vehicles.

Vehicles, such as motor vehicles, utilize an energy source in order toprovide power to operate the vehicle. While petroleum-based products,such as gasoline, dominate as an energy source in traditional combustionengines, alternative energy sources are available, such as methanol,ethanol, natural gas, hydrogen, electricity, solar, and/or the like. Ahybrid powered vehicle, referred to as a “hybrid vehicle,” utilizes acombination of energy sources in order to power the vehicle. Forexample, a battery may be utilized in combination with the traditionalcombustion engine to provide power to operate the vehicle. Such vehiclesare desirable because they take advantage of the benefits of multiplefuel sources in order to enhance performance and range characteristicsof the hybrid vehicle relative to a comparable gasoline-powered vehicle.

An example of a hybrid vehicle is a vehicle that utilizes a combinationof stored electric energy and an internal combustion engine as powersources to propel the vehicle. An electric vehicle is environmentallyadvantageous due to its low emissions characteristics and the generalavailability of electricity as a power source. The battery may be quitelarge, depending on the energy requirements of the vehicle, and willgenerate heat that is dissipated using various techniques. Batteries canbe quiet emitting low sound. Adjustment between a supplemental energysource, like an engine, can be improved to provide desired vehicleperformance characteristics.

SUMMARY

Various embodiments allow an electric or hybrid electric-powered vehicleto provide adjustment between using multiple energy sources andincreased performance related to environmental factors, power factors,and longevity factors. In various embodiments, a power and efficiencymanagement system for a vehicle is provided. In various embodiments,various operating modes can be employed by the driver to create adesired look, feel, and sound. In various embodiments, the life ofconsumable parts such as brake pads can be increased. Variousembodiments provide for an improved interaction between the engine andthe battery to provide added efficiency and performance.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 is a schematic block diagram of a drive system for a vehicleaccording to an exemplary embodiment of the disclosure.

FIG. 2 is a chart representing various modes according to an embodimentof the disclosure.

FIG. 3 illustrates a perspective view of an example steering wheelhaving a pair of hand pedals for adjusting between multiple operationalmodes according to an embodiment of the disclosure.

FIG. 4 illustrates a front view of an example steering wheel accordingto an embodiment of the disclosure.

FIG. 5 illustrates a left front view of an example pedal mounted on asteering wheel according to an embodiment of the disclosure.

FIG. 6 illustrates a right front view of an example pedal mounted on asteering wheel according to an embodiment of the disclosure.

FIG. 7 illustrates an example steering wheel according to an embodimentof the disclosure.

FIG. 8 illustrates an example pedal mounted on a steering wheelaccording to an embodiment of the disclosure.

FIG. 9 illustrates a side view of a pedal mounted on a steering wheelaccording to an embodiment of the disclosure.

FIG. 10 illustrates a front view of pedals according to an embodiment ofthe disclosure.

FIG. 11 illustrates a back side rear view of pedals according to anembodiment of the disclosure.

DETAILED DESCRIPTION

Referring to FIG. 1, a vehicle, such as a hybrid vehicle 20, includes arechargeable energy storage system (RESS) 22 coupled with an engine 24.The engine 24 may generally refer to any apparatus operable to augmentpower or range beyond the RESS 22. For example, the engine 24 can be aninternal combustion engine that consumes gasoline. The RESS 22 can be,for example (but not limited to) a high-voltage battery, such as ahigh-voltage lithium ion battery pack. The engine 24 may drive agenerator 25 to provide electrical power to an electrical (e.g., DC) bus30 to which the RESS 22 may be coupled. Operation of the vehicle 20 canbe driven by each power source and/or both. The vehicle 20 can includeone or more drive motors, such as a front wheel motor 26 and/or a rearwheel motor 28. The drive motors 26 and 28 can be electrically drivenand coupled to the engine 24 and the RESS 22 via the electrical bus 30.In one exemplary embodiment, the motors 26 and 28 may be DC motors.

In other embodiments, the motors 26 and 28 may be AC motors andinverters may be provided between the motors 26 and 28 and a DC bus 30.The motors 26 and 28 engage the front and/or rear drive shafts that turnone or more wheels of the vehicle. In an exemplary embodiment, the frontmotor 26 may drive the front wheels 40 via a front differential 42 andthe rear motor 28 may drive the rear wheels 44 via a rear differential46.

When the vehicle accelerates or increases energy consumption, speed ofthe drive motor increases to deliver more power or energy to the wheels.The turning of the motors can be reversed to provide regenerativebraking, which provides the impression of downshifting the vehicle. Thisalso generates energy that can be stored in the RESS. Accordingly, insome embodiments, the vehicle can actuate regenerative braking to slowthe vehicle rather than causing brake pads to slow the wheels of thevehicle when a brake pedal of the vehicle is depressed. To slow thevehicle beyond the speed caused by the regenerative braking, the brakepads can engage the wheels under predetermined circumstances that areinput into a controller of the vehicle. For instance, the brake pads cantake over once requested braking surpasses a prefixed set point orthreshold.

Various embodiments provide for one or more driver-selectable powertrainoperating modes for a vehicle such as a hybrid vehicle. In someembodiments, a first mode or “stealth” mode is a default operating modefor the vehicle. In stealth mode, fuel economy can be favored overperformance. To favor fuel economy, the vehicle is powered by the RESS(e.g., high-voltage battery) with little or no supplemental power fromthe engine. The RESS is used to operate the vehicle until the RESSreaches a first state of charge threshold. The first state of chargethreshold may be predetermined and programmed into a controller of thevehicle. The first state of charge threshold may be targeted to maintainbattery longevity and performance targets. In stealth mode, the vehiclecontroller is programmed to prevent engine operation until the RESSreaches its first target state of charge threshold.

Stealth mode allows for quiet vehicle operation for both a driver of thevehicle and to outside observers. Accordingly, this can provide adesired “stealth” look, feel, and sound. The vehicle can emit aparticular sound when operating in stealth mode that enhances the“stealth” impression. An external sound system composed of at least aspeaker and a sound controller can be included in and/or on the vehicle.The sound controller generates sounds based on vehicle and driverbehavior and sends the sounds to the speakers. For example, accelerationcan emit a first sound, braking can emit a second sound, and otherbehaviors like starting and turning off the vehicle can emit additionalsounds.

Stealth mode can affect the powertrain thermal strategy. Suitableheating and cooling management of batteries, motors, engines, powerelectronics, and/or the like can affect vehicle operation performance.For example, lower power limits or higher coolant temperature limits canbe specified in stealth mode to reduce fan and pump loads. Accordingly,the thermal system would not have to work as hard if the cooling needsare limited. This decrease in energy consumption may correspond tobetter fuel economy. In a further example, customer comfort requirementscan be relaxed for better fuel economy (e.g., by limiting power allowedfor seat heating).

Selection of stealth mode can affect other systems outside of thepowertrain system of the vehicle to correlate the driving experience toenvironmental-friendliness factors. In some embodiments, an acousticsignature of the vehicle can change via active interior and/or exteriorsound enhancement. In some embodiments, the vehicle includes a displayscreen displaying the vehicle along with other features. The featurescan be customizable. The visual appearance of the vehicle can change onthe display screen in stealth mode. Interior and/or exterior lightingcan further be changed when operating in stealth mode. Tactile feedbackto the driver may change as well.

A second mode or “sport” mode can be a selectable mode that emphasizesperformance aspects of the vehicle by allowing for engine operation toaid more than the RESS as compared to stealth mode. The system mayinclude a mechanism to allow the driver to switch between modes. Forexample, the driver can switch to sport mode and back to stealth via abidirectional push/pull sport hand paddle 11 on a steering wheel 10 asseen in FIGS. 3, 4, 5, 7, and 10. In the sport mode, the vehicle usesmore than one power source to achieve performance targets. The enginemay still turn off when the driver does not demand a lot of power, butwithout significantly sacrificing response time. Sport mode can affectvarious systems of the vehicle as well, but with the target of creatinga performance-oriented driving experience. In the sport and stealthmodes, the controller is configured to control the various systemcomponents (e.g., the engine, RESS, generator, motor, etc.) to operateas described further below.

The sport mode may be engaged or selected to provide additional powerfor the vehicle and/or to maintain the RESS at a predetermined secondstate of charge threshold. The second state of charge threshold may behigher than the first state of charge threshold. The vehicle may berequired in an all electric or stealth mode if, for example, the fuelsupply for the engine is exhausted or there is a malfunction in theengine. The second state of charge threshold, therefore, may beconfigured to provide the vehicle with sufficient stored energy suchthat the vehicle may be operated in an all-electric or stealth mode fora predetermined time period or range (e.g., approximately 26 miles). Forexample, the second state of charge threshold may correspond toapproximately sixty percent of total battery capacity. In anotherembodiment, the second state of charge threshold may correspond to afully charged battery or RESS.

If the sport mode is engaged when the state of charge of the RESS isbelow the second state of charge threshold, the engine may be engaged todrive the generator and provide electrical energy to the DC bus tooperate the drive motor(s) and charge the RESS. The sport mode may thenoperate as a “battery charging” sport mode and at least a portion ofthis electrical energy may then be utilized to charge the RESS until itreaches the second state of charge threshold. The engine and generatormay then be operated to maintain the RESS at the second state of chargethreshold and the vehicle is propelled by the drive motor(s) utilizingonly electric energy generated by the engine and generator.

If the sport mode is engaged when the state of charge of the RESS isabove the second state of charge threshold, the engine may be engaged todrive the generator and provide electrical energy to the DC bus tooperate the drive motor(s). The sport mode may then operate as a“battery depleting” sport mode and the RESS may be allowed to dischargeuntil it reaches the second state of charge threshold. The engine andgenerator may then be operated to maintain the RESS at the second stateof charge threshold and the vehicle is propelled by the drive motor(s)utilizing only electric energy generated by the engine and generator.

In another embodiment, the sport mode may be configured to maintain theRESS at the state of charge level of the RESS when the sport mode isengaged, independent of a second state of charge threshold as describedabove. The state of charge at which the RESS is maintained may begreater than or less than the second state of charge threshold. Forexample, if the state of charge level is approximately fifty percent ofa fully charged RESS, the engine would be controlled to maintain thestate of charge level at the fifty percent level. This embodiment may beused to reduce engine run time and emissions by eliminating the batterycharging sport mode.

The system may be controlled to operate in a combination of the batterydepleting mode and the battery maintaining or sustaining mode. Forexample, if the RESS state of charge level is greater than the secondstate of charge threshold the engine will be available to operate, butthe RESS will be allowed to discharge down to the second state of chargethreshold. If the RESS is at a stage of charge less than the secondstate of charge threshold when the sport mode is selected, the enginewill not operate to charge the RESS. Instead, the engine will operate tomaintain or sustain the state of charge at the current level presentwhen the sport mode was selected.

A third mode or “hill” mode can be a selectable mode that improvesdrivability of the vehicle. Hill mode is a form of electronicdownshifting using the RESS and the engine. In some embodiments, in hillmode, a suitable amount of resistance can be provided when drivingdownhill. This resistance may correlate to speed and can simulate thefeel of downshifting in a conventional vehicle. The driver can selectthe braking or hill mode using a mechanism. For example, the driver canchange hill mode via a bidirectional (push/pull) hill paddle 12 on thesteering wheel 10 as seen in FIGS. 3, 4, and 6-11.

In various embodiments, hill mode can include a plurality of selectablelevels of resistance. For example, three selectable levels of resistancemay be provided—H1, H2, and H3. This can be analogous, for example, tothree low gears in a transmission. A higher number indicates higherresistance (i.e., higher automatic regenerative braking). Eachsuccessive hill paddle 12 pull or push inputs change resistance, forexample: OFF→H1→H2→H3→OFF. The driver can also decrement the hillresistance by pushing the hill paddle 12. Any number of modes orengagement/disengagement orders can be employed.

In an example as shown in FIGS. 3-11, the sport paddle 11 and hillpaddle 12 are positioned on opposite sides of the steering wheel 10 neartypical or comfortable hand positions on the steering wheel 10. In thisexample, the sport paddle 11 is on a left side and the hill paddle 12 ison the right side. To communicate functionality to the driver, the words“sport” and “hill” can be formed on each of the respective paddles.

In various embodiments, the vehicle enters hill mode automatically bysensing the grade of the road, or vary resistance automatically within ahill mode. For example, a threshold grade can be input into a vehiclecontroller that is coupled to the transmission. A level sensor or GPSsystem may send a signal to the controller indicating that the vehiclewas driving along a certain grade that reached a preset threshold fordriving in hill mode. In some embodiments, the controller may cause thevehicle to switch to hill mode upon receiving the signal. In particularembodiments, the controller may cause the vehicle to switch to aparticular hill mode level that corresponds to the detected grade uponreceiving the signal.

In various embodiments, hill mode provides relatively consistentresistance regardless of vehicle conditions. Hill mode can generateresistance using several methods, including, but not limited toregenerative braking, using more electricity, engine braking, frictionbraking, and/or the like.

In some embodiments, regenerative braking may be used to generateresistance. In particular embodiments, the traction motors are engagedas generators to provide energy to the RESS. During downhill ordown-grade driving, the engine recharges the RESS.

In some embodiments, resistance may be generated by using moreelectricity (i.e., more electric energy than normal). The vehicle may dothis when the RESS has a full charge. Electrical systems of the vehiclewould receive energy either directly from the regenerative brakingsystem or from the RESS. The vehicle could use this energy to cool thebattery and motors more aggressively or effectively waste energy byrunning systems and components inefficiently that would not haveoperated otherwise. Wasting electrical energy is an alternative towearing down the brake pads. In some embodiments, electric motors can beused similarly to eddy current brakes by variably short circuiting theelectric motor phases through the inverters, thus dissipating energywithin the electric motors as heat.

In some embodiments, resistance may be generated by engine braking(e.g., dissipating energy by spinning the engine). If the engine canmechanically drive the wheels, this engine braking is similar to that ofa traditional automatic transmission vehicle. If, however, the enginehas no mechanical connection to the wheels, as in an example plug-inhybrid vehicle, the vehicle can still dissipate energy by spinning theengine with a generator. The generator would receive energy eitherdirectly from the regenerative braking system or from the RESS. Thevehicle may do this, for example, when the RESS has a full charge.Engine braking could maintain full hill mode resistance.

In some embodiments, resistance may be generated by friction braking(e.g., engaging brake pads and rotors). The vehicle may do this when theRESS has a full charge and the methods listed above cannot reasonablydissipate enough power or would otherwise be undesired (e.g., to do sowould cause severe wear). On a vehicle with regenerative braking, thebrake pads get much less use than a conventional vehicle. As such, theuse of the brake pads in this scenario would not significantly reduce(if at all) life of the brake pads below that of a conventional vehicle.

FIG. 2 is a chart representing travel down a steep, constant grade atconstant speed. It shows RESS state of charge (SOC), manually requestedbrake power, and brake power automatically engaged by hill mode(regenerative and dissipated). For the time associated with interval(a), hill mode is off (e.g., the vehicle is operating in either sport orstealth mode). The powertrain provides a minimum resistance by defaultwhen the brake pedal is not depressed. In this example, the brake pedalrequests the remaining majority of braking power to maintain constantspeed. The braking in time intervals (a) through (d) is regenerative,whether automatically requested based on operating mode or manuallyrequested by the brake pedal. The regenerative braking causes the RESSto store energy received from the regenerative braking.

During time interval (b), the vehicle is operating in hill mode 1 (H1).In H1, the powertrain provides more resistance (e.g., than either ofstealth or sport mode) when no brake pedals are depressed. The majorityof the braking power required to maintain constant speed is stillrequested by the brake pedal. However, the brake pedal is depressed lessthan in interval (a). FIG. 2 shows automatic brake power requested by H1at around 30% and brake pedal requested brake power at about 70%.

During time interval (c), the vehicle is operating in hill mode 2 (H2).In H2, the powertrain provides more resistance (e.g., than in H1) whenthe brake pedal is not depressed. The minority of the braking powerrequired to maintain constant speed is requested by the brake pedal. Inthis example, automatic hill mode braking power is about 70% and brakepedal-requested power is about 30%.

During time interval (d), the vehicle is operating in hill mode 3 (H3).In H3, the powertrain provides strong resistance when no brake pedalsare depressed so that the vehicle is maintained at a constant speed.Manually requested braking is at about 0% while the automatic braking isat about 100%.

During time interval (e), the vehicle is still operating in H3. As theRESS reaches its maximum SOC, the vehicle transitions from storingenergy to dissipating energy, for example, using (but not limited to)the methods provided in the disclosure. This allows the drivingexperience to remain consistent regardless of the RESS SOC.

In various embodiments, stealth mode provides a look, feel, and/or soundassociated with advanced technology. This effect, for example, canprovide a sense of stealth jets, military technology, spyJames-Bond-style technology, and/or the like. In various embodiments,stealth mode also highlights the acoustic signature of the vehicle inelectric operation, particularly because the electric powertrain runsquietly.

The term “sport” is commonly used in the automotive industry toassociate with acceleration, speed, and handling performance. Accordingto various embodiments, sport mode may be associated with a hybridvehicle using more than one power source to achieve performance targets.

In various embodiments, hill mode may be used in various circumstancesto reduce the need for traditional braking. For example, when thevehicle is in heavy traffic or other related situations, hill mode maybe implemented to take advantage of regenerative braking rather thanmanual braking.

In various embodiments, hill mode allows the vehicle to vary gearing ordownhill resistance continuously with controls or a specialtransmission, e.g. continuously, infinitely, or electronically variabletransmission (CVTs, IVTs, & EVTs). In an example, the vehicle has onlyone gear ratio between the drive motors and the wheels and fully blendedregenerative braking.

FIGS. 3-11 relate to example steering wheels 10 for an example vehicleassociated with the modes described in the disclosure. FIGS. 3-9 show anexample steering wheel 10 having a sport hand paddle 11 and a hill handpaddle 12 mounted in opposite positions. A center portion 13 provides anaesthetic cover for various electrical components associated with atleast the paddles 11 and 12. The dashboard 14 can include a display forshowing various mode operations as well as speed and other associatedvehicle conditions. FIGS. 10 and 11 illustrate example hand paddles forsport paddle 11 and hill paddle 12. Each paddle can identify the word“sport” and “hill” respectively for the added convenience of the driver.Although the paddles 11 and 12 are positioned near the circumference ofthe steering wheel at convenient hand positions for a typical driver, itis understood that the paddles can be disposed at various positions onthe wheel or in the vehicle.

The previous description of the disclosed embodiments is provided toenable any person skilled in the art to make or use the presentdisclosure. Various modifications to these embodiments will be readilyapparent to those skilled in the art, and the generic principles definedherein may be applied to other embodiments without departing from thespirit or scope of the disclosure. Thus, the present disclosure is notintended to be limited to the embodiments shown herein but is to beaccorded the widest scope consistent with the principles and novelfeatures disclosed herein.

What is claimed is:
 1. A system for controlling a mode of operation of adriver operated vehicle having a rechargeable energy storage system(RESS), an engine configured to drive an electrical generator, and adrive motor coupled to the RESS and the engine, the drive motorselectively powered by at least one of the RESS and the engine, thesystem comprising: a controller operable to adjust the vehicle tooperate in at least two operating modes including a first mode ofoperation in which the drive motor is powered only by the RESS and asecond mode of operation in which the drive motor is powered byelectrical power provided by the engine driven generator; a switch forthe driver to select either the first mode of operation or the secondmode of operation; a second switch for the driver to select either afirst mode of braking operation or a second mode of braking operation;wherein when the driver operates the switch to select the first mode ofoperation the controller is configured to maintain the system in thefirst mode of operation and ensure that the only power source for thedrive motor is the RESS regardless of the power demanded by the driver;wherein when the driver operates the switch to select the second mode ofoperation the controller is configured to operate the engine to generateelectric power for the drive motor; wherein, when the second mode ofoperation is selected, the controller is configured to operate theengine as necessary to maintain the RESS at or above a predeterminedstate of charge; wherein, the controller is configured to automaticallyswitch the mode of braking operation when the vehicle detects a gradechange in a road through one of a level sensor and a Global PositioningSystem (GPS).
 2. The system of claim 1, wherein the controller isconfigured to automatically shift the vehicle to the second mode ofoperation when the RESS reaches a target state of charge threshold. 3.The system of claim 2, wherein the predetermined state of charge isgreater than the target state of charge threshold.
 4. The system ofclaim 1, wherein the switch for selecting the mode of operation of thevehicle includes a driver interface that located on the steering wheel;and wherein the vehicle includes an external sound system for emittingsounds when the vehicle is in first mode to indicate behaviors includingone of acceleration, braking, and starting the vehicle.
 5. The system ofclaim 1, wherein in the first mode of braking operation a first amountof regenerative braking is provided when a brake pedal is not depressed.6. The system of claim 5, wherein in the second mode of brakingoperation a second amount of regenerative braking is provided when thebrake pedal is not depressed.
 7. The system of claim 6, wherein thesecond amount of regenerative braking is greater than the first amountof regenerative braking.
 8. The system of claim 5, wherein the secondswitch includes a driver interface located on the steering wheel.
 9. Asystem for controlling a mode of operation of a driver operated vehiclehaving a rechargeable energy storage system (RESS); an engine configuredto drive an electrical generator, and a drive motor coupled to the RESSand the engine, the drive motor selectively powered by at least one ofthe RESS and the engine, the system comprising: a controller operable toadjust the vehicle to operate in at least two operating modes includinga first mode of operation in which the drive motor is powered only bythe RESS and a second mode of operation in which the drive motor ispowered by electrical power provided by the engine driven generator; aswitch for the driver to select either the first mode of operation orthe second mode of operation; a second switch for the driver to selecteither a first mode of braking operation or a second mode of brakingoperation; wherein when the driver operates the switch to select thesecond mode of operation the controller is configured to operate theengine to generate electric power for the drive motor; wherein, when thesecond mode of operation is selected by the driver, the controller isconfigured to operate the engine as necessary to maintain the RESS at anexisting state of charge level present when the second mode of operationis selected by the driver; wherein, the controller is configured toautomatically switch the mode of braking operation when the vehicledetects a grade change in a road through one of a level sensor and aGlobal Positioning System (GPS).
 10. The system of claim 9, wherein whenthe driver operates the switch to select the first mode of operation thecontroller is configured to maintain the system in the first mode ofoperation and ensure that the only power source for the drive motor isthe RESS regardless of the power demanded by the driver.
 11. The systemof claim 9, wherein, when the first mode of operation is selected by thedriver, the controller is configured to automatically shift the vehicleto the second mode of operation when the RESS reaches a target state ofcharge threshold.
 12. The system of claim 9, wherein the switch forselecting the mode of operation of the vehicle includes a driverinterface is located on the steering wheel; and wherein the vehicleincludes an external sound system for emitting sounds when the vehicleis in first mode to indicate behaviors including one of acceleration,braking, and starting the vehicle.
 13. The system of claim 9, wherein inthe first mode of braking operation a first amount of regenerativebraking is provided when a brake pedal is not depressed.
 14. The systemof claim 13, wherein in the second mode of braking operation a secondamount of regenerative braking is provided when the brake pedal is notdepressed.
 15. The system of claim 14, wherein the second amount ofregenerative braking is greater than the first amount of regenerativebraking.
 16. The system of claim 13, wherein the second switch is partof a driver interface located on the steering wheel.